Many applications involve heating. Efficiency, precise control, convenience, size, and usability can be concerns with existing techniques for establishing or adjusting temperature of a target object or space.
Spetz U.S. Pat. No. 7,429,719 provides a self-regulating heater using a semiconductor as a heating element that has a fast response and is temperature limited. A biasing network operates the semiconductor to cause the semiconductor to conduct more current at lower temperatures and less current at higher temperatures. Spetz uses a field-effect transistor (FET) as a heat source and then drains the resulting current out the FET in a loop around the semiconductor in order to complete the circuit for the pass-through current.
Wander U.S. Patent Publication No. 20110226759 discusses an example of applying microwaves to a semiconductor wafer to heat the semiconductor wafer. Wander uses a microwave cavity as the energy source, and merely places the semiconductor in the cavity as a bulk target to be heated, without providing any ability to localize heat production or gradients at one or more particular locations within the semiconductor substrate.